In response to the recent Environmental Protection Agency (EPA) announcement that affirmed a national standard for maximum arsenic content in drinking water of 10 parts per billion (ppb), ADA Technologies, Inc. is proposing to develop and commercialize a novel, low-cost sorbent for the removal of arsenic and other heavy metals from drinking water. ADA has assembled a project team with a complementary mix of experience and skills to develop the sorbent and to package it for use in small and large-scale water treatment systems. The sorbent will combine novel technology from ADA to chemically amend a substrate clay material to increase its capacity for arsenic with emerging technology from Texas A&M to bind the clay to sand or other materials that increase the porosity of the sorbent and allow its use in water treatment. The Texas A&M technology has been developed with funding from the NIEHS under the Superfund Basic Research Program (SBRP), addressing one of the recommendations in the solicitation to which this proposal responds. The expertise of CH2M-Hill, an internationally known architect/engineering firm, will be tapped to package the novel sorbent in configurations that are amenable to use in commercial-scale water treatment systems. The overall goal of the project is to demonstrate the cost-effective removal of arsenic from groundwater using the amended clay sorbent technology. Specific activities include the preparation of several variants of the new sorbent, completion of laboratory tests to optimize the formulation, design and fabrication of prototype hardware in two sizes, and ten-month field trials of both pilots on arsenic-contaminated waters in Colorado's San Luis Valley, an area with arsenic content in excess of the new EPA standard.